When is a wa­ter­bird not a wa­ter­bird?

All our UK grebes win high marks for good looks, from the neat, cute Lit­tle Grebe, through the strik­ing Slavo­nian and Black-necked Grebe, to the now-fa­mil­iar Great Crested Grebe. You might ex­pect them to be closely re­lated to the divers, given that the two fam­i­lies turn up in the same sorts of habi­tats, and share a num­ber of be­havioural and struc­tural traits. In fact, though, this is merely an ex­am­ple of con­ver­gent evo­lu­tion, of which much more later. So, are they re­lated to wild­fowl, or other wa­ter­birds? Well, not re­ally, although their clos­est rel­a­tives are also associated with wa­ter. In fact, re­cent stud­ies sug­gest that grebes have at least 11 mor­pho­log­i­cal traits in com­mon with flamin­gos – some­thing to pon­der when you see flocks of bright pink Greater Flamin­goes on coastal la­goons in Spain and Por­tu­gal, with Lit­tle Grebes dab­bling around near their feet. Trac­ing the fam­ily line fur­ther, both grebes and flamin­gos are re­lated to doves and sand­grouse, in the tax­o­nomic clade Colum­bea.

A QUES­TION OF SCALE Lit­tle Grebes are dwarfed by flamin­gos, but they’re ac­tu­ally very close rel­a­tives